* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
ul {
  list-style: none;
}
.a1 {
	position: absolute;
	top: 50%;
	left: 50%;
	transform: translate(-50% ,-50%);

}
#b1 {
  width: 1200px;
  height: 600px;
  background:  url(../img/元旦快乐.jpg) center / cover no-repeat;
  border-radius: 5px;
  background-size: 1200px 600px;
}

#b1 > [class=a2] {
	width: 41px;
	height: 69px;
	position: absolute;
	top: 50%;
	transform: translate(0,-50%);
  line-height: 69px;
cursor: pointer;

}
#b1 > [class=a3] {
	width: 41px;
	height: 69px;
	position: absolute;
	top: 50%;
	transform: translate(0,-50%);
  line-height: 69px;
cursor: pointer;

}

#b1 > .a2 {
  background: url(../img/anniu.png) 82px center;
  left: 10px;
}

#b1 > .a3 {
  background: url(../img/anniu.png) 41px center;
  right: 10px;
}

#b1 > .a2:hover {
  background-position: 0;
}

#b1 > .a3:hover {
  background-position: -42px center;
}

#b1 > .a4 {
  padding: 10px;
  position: absolute;
  bottom: 20px; 
  right: 30px;
}

#b1 > .a4 li {
  float: left;
  width: 10px;
  height: 10px;
  border-radius:50%;

  
  border: 2px solid hsla(0,0%,100%,.3);
  background-color: rgb(0 0 0 / .4);
  margin: 0 4px;
}

#b1 > .a4 li.active {
  background: hsla(0,0%,100%,.4);
  border-color: rgb(0 0 0 / .4);
}
